Affiliations: [a] Department of Sports Medicine and Prevention,
University of Potsdam, Germany | [b] Medical Clinic, Department of Rehabilitative and
Preventive Sports Medicine, University of Freiburg, Germany
Note: [] Adress for correspondence: Steffen Müller, University of
Potsdam, Department of Sports Medicine and Prevention, Am Neuen Palais 10 Haus
12, 14469 Potsdam, Germany. Tel.: +49 331 977 1127; Fax: +49 331 977 1296;
E-mail: Steffen.Mueller@uni-potsdam.de
Abstract: The purpose of this study was to analyse the reproducibility of
isokinetic single-joint (knee and ankle) and multi-joint (leg-press
configuration) strength findings in healthy athletes and a group of athletes
with chronic unilateral tendon injuries at the lower limb, over a clinically
meaningful time interval of 8 weeks. Concentric and eccentric strength
performance capacity of knee extensors/flexors, ankle dorsi-/plantarflexors as
well as the extensors of the total lower limb was assessed twice in 19 healthy
(H) and 10 injured (I) athletes. Calculation of ICC, standard error of
measurement SEM, Bland and Altman's 95% limits of agreement and Test-Retest
Variability (TRV) served as main outcome variables. The results showed a small
systematic bias and random error [mean bias: 3.25 ± 4.02
(H) 4.25 ± 4.56 (I); TRV 12.34 ±
10.20% (H) 14.27 ± 9.42% (I)] except for plantarflexion measurements
and the eccentric mode of the total lower limb strength in injured athletes
(TRV � 20%). The present findings delineate
clinically relevant cutoff values in the evaluation of valid intervention
effects of strength training and rehabilitation in healthy athletes and
athletes suffering from tendon-related injuries.
